Gasperini was furious with Zaniolo for taunting the Cagliari fans during his goal celebration after grabbing the winner on the day.
"Zaniolo scored a good goal and had some good moves when he came on, he has certainly improved in terms of his dynamism,” said the coach.
“He has to work more on maintaining the right position and defending, especially in the final stages.
“What we cannot afford is that every tine he scores a goal, he fires up the crows and turns an advantage into a disadvantage. At that moment, Cagliari were stunned and we managed to create a situation where the crowd fired them up again.
“This is already the second time he has done that and it is intolerable.”
Gasperini also said: “I have a very competitive squad that at times, when not all 11 are playing together, manages to cover for the difficulties of some others. However, if we want to stay where we are in the table, we need to improve.
“If I have to reproach the team for something, it’s that we could’ve been more effective in attack during the closing stages and therefore suffered less.
“Fortunately, we have some warriors who are accustomed and ready to defend in this type of match, even when we are a man down.”